10 May 2006 Temperature dependence of detection limits of TNT on metallic surfaces using fiber optic coupled FTIR
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Abstract
Fourier transform infrared (FTIR) spectroscopy has been established as well suited for work outside the confinement of the sample compartment, provided the excitation source and the reflected light can be transported to the interferometer. Fiber optic cables that transmit in the Mid-IR range have made this possible by allowing the development of a series of spectroscopic probes for in situ analysis. In previous work it was established that surface concentrations of TNT as low as 0.3 μg/cm2 (300 ng/cm2) could be detected with high confidence level. This detection limit varies according to macro properties. Properties such vapor pressure, physical adsorption, sublimation rate and surface-adsorbate thermodynamics can influence the detection limit. A close relation between vapor pressure and limit detection is shown for nitroexplosives. The amount of explosive and the residence time on stainless steel depends on this property, because at low surface concentrations the explosive goes to the vapor phase fast. Loading concentrations near the limits of detection were prepared and spectra were recorded at different temperatures in the range of 14-30°C. The nitro band was monitored for the experiments and the data was analyzed by using peak areas and Chemometrics. A close relationship between the detection limit and temperature was observed.
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Yadira Soto-Feliciano, Oliva M. Primera-Pedrozo, Leonardo Pacheco-Londoño, Samuel P. Hernandez-Rivera, "Temperature dependence of detection limits of TNT on metallic surfaces using fiber optic coupled FTIR", Proc. SPIE 6201, Sensors, and Command, Control, Communications, and Intelligence (C3I) Technologies for Homeland Security and Homeland Defense V, 62012H (10 May 2006); doi: 10.1117/12.665897; https://doi.org/10.1117/12.665897
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